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Re: How best to inexpensively clean degraded variable caps?
Gary DeBock
On Mon, Jul 13, 2020 at 07:26 PM, Guy Atkins wrote:
It's tough to beat the excellent "Q" of a top-notch air variable cap!
Amen to that, home town brother! The reality is that when you spend some serious vacation $$ to show up at an ocean side cliff and/ or exotic overseas ocean beach with FSL antennas and completely depend on the FSL's tuned gain performance to give you DXing success, you had better deploy with with the sharpest variable cap(s) that you can track down. The cost of all-new variable cap upgrades is always less than 10% of the total vacation cost. Of course I'm aware that most FSL users chase DX with these antennas in the shack, under far less demanding conditions. A variable cap that has minor issues because of oxidation or a less-than-successful cleaning attempt is not going to be a major deal breaker in routine, home town DXing. It's only when you are trying for something bordering on the "impossible" in extremely tough conditions (like chasing African AM-DX at over 8,000 miles at sunset in Hawaii on a 5" FSL) that a degraded variable cap will almost certainly shoot you down. These receptions are barely possible anyway, even with superior propagation and a razor-sharp 5 inch gain antenna. <<< A simple enough approach to give a modicum of weather resistance to the caps--and forestall weathering-- is to build the FSL components inside of a tote box. I describe that method here: https://swling.com/blog/2017/01/a-new-approach-to-fsl-antenna-construction/ >>> Guy's approach is good, and would stop any degradation due to salt water air exposure. Even in all the FSL antennas previously deployed to ocean side cliffs and overseas ocean beaches there has always been a waterproof vinyl covering designed to stop rain from throwing off the variable cap tuning, but obviously some oxidation has still been occurring over years of time, throwing off the variable cap performance somewhat. DXers can address this issue any way they prefer, but for the FSL antennas heading for the Rockwork Cliff DXpedition coming up soon, not only will the variable caps be brand new, but the FSL antenna designs will be brand new, developed during the extended tinkering hours of the Pandemic. These combine powerful tuned gain with much lighter weight (and much lower cost) than the 15" and 17" Monster FSL antennas used previously. Shown in the attached design photos, they deliver equivalent performance in a much more user-friendly package. Their construction cost would probably still derail most hobby budgets, but is less than half of the $1K Monster FSL's. Gary DeBock (in Puyallup, WA, USA)
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Re: How best to inexpensively clean degraded variable caps?
Guy Atkins
My method has been 91% isopropyl alcohol, using a long bristle, very soft brush for working the liquid down between the vanes. I don't worry too much about washing out the bearing grease as I prefer to just re-grease the pivot points (Caig De-Oxit L260D lithium grease) after blowing out the remaining alcohol with compressed air. The thought of using a micro-controller and stepper motor (mentioned earlier) to move the variable cap makes me shudder at the chance of creating RFI anywhere near these sensitive FSL antennas, much less the introduced mass of metal nearby. This approach was something I tried years ago while trying to create a viable remotely-tuned FSL, but I decided the complexity of motors etc. wasn't worth it. Varactor diodes aren't worthwhile either, as have been discussed at length in the forum. It's tough to beat the excellent "Q" of a top-notch air variable cap! A simple enough approach to give a modicum of weather resistance to the caps--and forestall weathering-- is to build the FSL components inside of a tote box. I describe that method here: https://swling.com/blog/2017/01/a-new-approach-to-fsl-antenna-construction/73, Guy Atkins Puyallup, WA
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Re: How best to inexpensively clean degraded variable caps?
I will (eventually) put a large two section variable cap, with three to one gear drive, in my ultrasonic cleaner and see what happens. It was new old stock, so it isn't decades old and covered with nicotine and such, but it has been sorely mistreated, having been damaged in a tip over of a box loop. That required many hours of careful 'forming' to eliminate contact between plates and equalize the spacing. It works fine now. I want to try it in an FSL once my ferrite rods and Litz wire get here. Then I will subject it to ultrasonic cleaning and see if I can notice any difference afterwards. I don't expect to be able to notice any difference at all, but I am willing to be surprized.
BTW, I found 50 meters of 200/46 Litz for only $28 US with free shipping. Nice for an inexpensive 3 or 4 foot air core loop to compare to the FSL. https://www.ebay.com/i/163918891324?chn=ps?_ul=MX
Regards,
Gord
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Re: How best to inexpensively clean degraded variable caps?
Thanks Jay!
I don't think I ever used DeOxit without a 91-99% wash afterward because of residue. However, it seemed that DeOxit might do a better job of removing oxidation if used first. The alcohol wash seemed to work just as well, as an afterthought, and is certainly less expensive and with essentially no residue at all. By the way, I use 91-99% spray alcohol as a 'dry cleaner' for clothes and such all the time and it is a good contact disinfectant in this time of Coronavirus too.....
Dave Aichelman N7NZH Grants Pass, Oregon
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Re: How best to inexpensively clean degraded variable caps?
De-Ox-It is not the best way to clean dirty cap plates...it is a contact cleaner/enhancer designed to improve conductivity between two metal parts. I have successfully cleaned caps in vintage radios with 91% Isopropyl alcohol, blowing it out with compressed air. This is cured several tuning caps that crackled when tuned or even shorted out in places.
i recommend 91% Isopropyl mainly because it leaves less residue than 70% which may have other additives in addition to water.
I HAVE used De-Ox-It on the contact points in tuning caps, using the pinpoint applicator rather than the usual spray. That has worked well.
Jay
https://radiojayallen.com
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Re: How best to inexpensively clean degraded variable caps?
It would be good to prevent the oxidisation in the first place. This would need a hermetically sealed environment with a desiccant but getting a device that needs manual operation into a sealed box is difficult.
For the microcontroller-minded, a stepper motor, EasyDriver module and code adapted from BrainyBits could be a good starting point for remote operation.
https://www.brainy-bits.com/stepper-motor-easy-driver/ The whole shebang could be kept in an air-tight box with only the controller and wiring being outside. It does, however, put a substantial
mass of ferromagnetic metal near the FSL.
A compromise might be to keep capacitor exposure to air to a minimum. This means keeping the FSL in an airtight enclosure with desiccant as much as possible and exposing it to air only during use. Won't eliminate oxidisation but should slow it down.
Back in the dimdarks, when vacuum-tubes ruled, we used copper sulphate crystals as desiccant to keep moisture-sensitive components dry. When the crystals turned pink, they were refurbished by being dried out in a box with an incandescent lamp (only set fire
to the workshop once).
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From: main@UltralightDX.groups.io <main@UltralightDX.groups.io> on behalf of daiche via groups.io <daiche@...>
Sent: Saturday, 11 July 2020 4:19 AM
To: main@UltralightDX.groups.io <main@UltralightDX.groups.io>
Subject: Re: [UltralightDX] How best to inexpensively clean degraded variable caps?
As far as expensive, yes DeOxit isn't cheap, but then it doesn't look like you need to buy a new capacitor at $20-$60 either and can refresh existing ones multiple times, instead of replacing. Alcohol is cheap and seems to work good too. Both can be used
without cap removal in many cases. Dawn soap, water and a fine long-bristled brush would work too, but you would need to remove, clean, dry and possibly relube the bearings and gearing before reinstalling the cap. I like the spray clean and canned air dry
method the best!
Dave Aichelman N7NZH Grants Pass, Oregon
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Re: How best to inexpensively clean degraded variable caps?
As far as expensive, yes DeOxit isn't cheap, but then it doesn't look like you need to buy a new capacitor at $20-$60 either and can refresh existing ones multiple times, instead of replacing. Alcohol is cheap and seems to work good too. Both can be used without cap removal in many cases. Dawn soap, water and a fine long-bristled brush would work too, but you would need to remove, clean, dry and possibly relube the bearings and gearing before reinstalling the cap. I like the spray clean and canned air dry method the best!
Dave Aichelman N7NZH Grants Pass, Oregon
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Re: How best to inexpensively clean degraded variable caps?
Hi Steve and all!
I first tried DeOxit D5, with a spray alcohol rinse afterwards and lastly spray air to dry off the residue. I have also tried spray alcohol by itself, which seemed to work fine by too. I always used spray air to blow off residue afterwards.
As far as what the residue is, could be salt spray, especially for those who hangout at ocean cliffside locations. I was thinking more the type of crude found in typical city pollution, which gets into everything over time and leaves a film. I will leave it to the chemists among us to figure out how it affects variable capacitors, but it seems to affect the Q, dulling the response. Sounds like we need a drive-thru capacitor washing service. I am sure there is lots of money to be made there, to freshen those dull variable capacitors! Your mileage may vary, depending on where you live and hangout. Ha!
Dave Aichelman N7NZH Grants Pass, Oregon
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Re: How best to inexpensively clean degraded variable caps?
Now we need to find the least expensive method of cleaning
variable caps not requiring (very) expensive DeOxit spray cleaner.
Would cheap drugstore isopropyl alcohol work well enough? Maybe
used in a spray bottle? Or perhaps something less expensive from
the hardware store? I don't have any degraded variable caps to
test cleaning methods on, so someone else will have to try.
73,
Steve
On 7/10/2020 2:56 AM, Gary DeBock via
groups.io wrote:
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Show quoted text
Thanks Steve (and Dave),
The possibility that the "Q" of older variable caps degrades over
time because of environmental factors is interesting, and I
appreciate your experimentation regarding this. That would
certainly explain why the brand new variable caps from Mike's
Electronic Parts always seem like hot performers out of the box,
while the older ones installed years ago seem like duds by
comparison. By coincidence I had replaced all of the variable caps
in the larger Rockwork Cliff "DXpedition" FSL antennas prior to
last year's trip, and did notice improved tuning performance.
<<< This is beginning to lend credence to Dave
Aichelman's comments about these caps seem to deteriorate in
selectivity/Q when used in FSLs that are exposed to cruddy
conditions such as coastal salt air, and that cleaning the cap
can restore it to "as-new" condition. >>>
I should thank Dave personally for this information, since
during the past week I've had several requests from DXers who
want me to replace the variable caps in their FSL's with the
latest models, and now it seems that this type of work can be
done by the DXer himself, without any effort on my part :-)
As for the "cruddy conditions" such as coastal salt air, Steve,
I can certainly appreciate how that would accelerate the
degradation of a variable cap. But in reality those kind of
coastal locations frequently are ideal DXing venues for the
compact FSL antennas, such as the wacky Rockwork Cliff in
Oregon, where Tom R. has completely shattered the west coast
record for South Pacific NDB's received during a DXpedition.
Overseas salt water beaches are also prime FSL DXing venues, and
they frequently combine extreme heat and humidity along with
their salt air corrosion. I suppose it's a situation similar to
pushing a race car constantly for top performance-- before you
show up at a challenging race track, you need to "pay the piper"
with new tires, new brakes and a perfectly tuned engine in order
to be competitive. Before using FSL antennas at an exotic beach
involving some serious travel $$, installing a brand new
variable cap (or detailed cleaning of an old one) should be
considered mandatory.
73, Gary
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Re: Tests of variable capacitors using Q meter including latest "0219" version Oren Elliott cap
Tom Crosbie G6PZZ <tom@...>
An extremely enlightening discussion. It reminds me of customers trading in gear who handed over a box with nicotine stained fingers and you just dreaded taking the
kit out. White lettering turned yellow by heavy smoking and fans in the back dragging the same in through every vent slot. We cleaned it all off as best we could, but it was a lot of man-hours making it ready for sale…
As a DXer keenly awaiting delivery of a baby FSL, it has certainly given me food for thought when I visit costal locations. I recall Paul Blundell’s efforts in operating
his inside a plastic tote box. From photographs taken at Rockworks etc., I see the FSL’s are covered in what I presume to be some kind of waterproof fabric. It seems this is not as waterproof as one might think. I would have thought that’s a bit high up for
direct saltwater spray but with cars and truck roaring past creating wind that blows exhaust fumes, road debris, rain and who knows what in all directions. Down on the beach it’s a similar story. More at risk of sea spray, even a gentle breeze can blow sand,
pollen from grasses and other vegetation.
Perhaps this calls for a holistic approach to mitigate the problem.
Gary, would it be possible to mount the 384P inside a small watertight plastic box? A clear box to see the vanes. I’m thinking a small hole drilled to take the Litz
wire could be sealed with hotmelt glue. The shaft could be fed through a tightly fitting grommet in another hole. This might mean the supporting PVC pipe needs to be an inch or so longer, but I suspect Gary has shares in his supplier
😊
Just an idea from someone with zero field experience of FSL’s – yet!
73 Tom G6PZZ
Nr Chesterfield | NE Derbyshire | UK | IO93he
HF250 | Sentinel 4 | RSPdx | RM50 | TR2 | ATS 808
15m MLB | MTA | D707
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Show quoted text
From: main@UltralightDX.groups.io <main@UltralightDX.groups.io>
On Behalf Of Gary DeBock via groups.io
Sent: 10 July 2020 10:56
To: main@UltralightDX.groups.io
Subject: Re: [UltralightDX] Tests of variable capacitors using Q meter including latest "0219" version Oren Elliott cap
Thanks Steve (and Dave),
The possibility that the "Q" of older variable caps degrades over time because of environmental factors is interesting, and I appreciate your experimentation regarding this. That would certainly explain why the brand new variable caps from Mike's Electronic
Parts always seem like hot performers out of the box, while the older ones installed years ago seem like duds by comparison. By coincidence I had replaced all of the variable caps in the larger Rockwork Cliff "DXpedition" FSL antennas prior to last year's
trip, and did notice improved tuning performance.
<<< This is beginning to lend credence to Dave Aichelman's comments about these caps seem to deteriorate in selectivity/Q when used in FSLs that are exposed to
cruddy conditions such as coastal salt air, and that cleaning the cap can restore it to "as-new" condition. >>>
I should thank Dave personally for this information, since during the past week I've had several requests from DXers who want me to replace the variable caps in their FSL's with the latest models, and now it seems that this type of work can be done by the DXer
himself, without any effort on my part :-)
As for the "cruddy conditions" such as coastal salt air, Steve, I can certainly appreciate how that would accelerate the degradation of a variable cap. But in reality those kind of coastal locations frequently are ideal DXing venues for the compact FSL antennas,
such as the wacky Rockwork Cliff in Oregon, where Tom R. has completely shattered the west coast record for South Pacific NDB's received during a DXpedition. Overseas salt water beaches are also prime FSL DXing venues, and they frequently combine extreme heat
and humidity along with their salt air corrosion. I suppose it's a situation similar to pushing a race car constantly for top performance-- before you show up at a challenging race track, you need to "pay the piper" with new tires, new brakes and a perfectly
tuned engine in order to be competitive. Before using FSL antennas at an exotic beach involving some serious travel $$, installing a brand new variable cap (or detailed cleaning of an old one) should be considered mandatory.
73, Gary
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Re: Tests of variable capacitors using Q meter including latest "0219" version Oren Elliott cap
Great posts and some interesting thoughts on the difference that time and use has on these. I keep mine very well protected.
Thanks Steve (and Dave),
The possibility that the "Q" of older variable caps degrades over time because of environmental factors is interesting, and I appreciate your experimentation regarding this. That would certainly explain why the brand new variable caps from Mike's Electronic Parts always seem like hot performers out of the box, while the older ones installed years ago seem like duds by comparison. By coincidence I had replaced all of the variable caps in the larger Rockwork Cliff "DXpedition" FSL antennas prior to last year's trip, and did notice improved tuning performance.
<<< This is beginning to lend credence to Dave Aichelman's comments about these caps seem to deteriorate in selectivity/Q when used in FSLs that are exposed to cruddy conditions such as coastal salt air, and that cleaning the cap can restore it to "as-new" condition. >>>
I should thank Dave personally for this information, since during the past week I've had several requests from DXers who want me to replace the variable caps in their FSL's with the latest models, and now it seems that this type of work can be done by the DXer himself, without any effort on my part :-)
As for the "cruddy conditions" such as coastal salt air, Steve, I can certainly appreciate how that would accelerate the degradation of a variable cap. But in reality those kind of coastal locations frequently are ideal DXing venues for the compact FSL antennas, such as the wacky Rockwork Cliff in Oregon, where Tom R. has completely shattered the west coast record for South Pacific NDB's received during a DXpedition. Overseas salt water beaches are also prime FSL DXing venues, and they frequently combine extreme heat and humidity along with their salt air corrosion. I suppose it's a situation similar to pushing a race car constantly for top performance-- before you show up at a challenging race track, you need to "pay the piper" with new tires, new brakes and a perfectly tuned engine in order to be competitive. Before using FSL antennas at an exotic beach involving some serious travel $$, installing a brand new variable cap (or detailed cleaning of an old one) should be considered mandatory.
73, Gary
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Re: Tests of variable capacitors using Q meter including latest "0219" version Oren Elliott cap
Gary DeBock
Thanks Steve (and Dave),
The possibility that the "Q" of older variable caps degrades over time because of environmental factors is interesting, and I appreciate your experimentation regarding this. That would certainly explain why the brand new variable caps from Mike's Electronic Parts always seem like hot performers out of the box, while the older ones installed years ago seem like duds by comparison. By coincidence I had replaced all of the variable caps in the larger Rockwork Cliff "DXpedition" FSL antennas prior to last year's trip, and did notice improved tuning performance.
<<< This is beginning to lend credence to Dave Aichelman's comments about these caps seem to deteriorate in selectivity/Q when used in FSLs that are exposed to cruddy conditions such as coastal salt air, and that cleaning the cap can restore it to "as-new" condition. >>>
I should thank Dave personally for this information, since during the past week I've had several requests from DXers who want me to replace the variable caps in their FSL's with the latest models, and now it seems that this type of work can be done by the DXer himself, without any effort on my part :-)
As for the "cruddy conditions" such as coastal salt air, Steve, I can certainly appreciate how that would accelerate the degradation of a variable cap. But in reality those kind of coastal locations frequently are ideal DXing venues for the compact FSL antennas, such as the wacky Rockwork Cliff in Oregon, where Tom R. has completely shattered the west coast record for South Pacific NDB's received during a DXpedition. Overseas salt water beaches are also prime FSL DXing venues, and they frequently combine extreme heat and humidity along with their salt air corrosion. I suppose it's a situation similar to pushing a race car constantly for top performance-- before you show up at a challenging race track, you need to "pay the piper" with new tires, new brakes and a perfectly tuned engine in order to be competitive. Before using FSL antennas at an exotic beach involving some serious travel $$, installing a brand new variable cap (or detailed cleaning of an old one) should be considered mandatory.
73, Gary
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Tests of variable capacitors using Q meter including latest "0219" version Oren Elliott cap
I received my Mike's Electronics latest version of the Oren
Elliot-manufactured latest version "0219" N50-384P variable cap
with vernier today.
There is a way to test the relative Q of a capacitor on the Q
meter using a reference inductor. You use your best cap as the
reference cap noting its Q at the various test frequencies. Then
you test other caps and see how their Q's compare to the best cap.
My best variable cap is the so-called "holy grail" TRW variable
capacitor from the URM-25D signal generator--it has ceramic
insulation, silver-plated plates, etc. Xtal Set DXers prize this
cap as the best. It has a 14-495 pF range, quite a bit higher max
capacitance than the nominal 385 pF of the N50-384P. Of course one
just sets the cap to the same 385 pF when testing. I have two
older Oren Elliott caps, both unused, so with the latest one I
have 3 of them to compare. I have a number of Russian caps with
vernier tuning and ceramic insulation that used to be inexpensive
and plentiful on eBay 5-10 years ago (in the $5-8 range)--now only
one or two sellers offer them at much higher prices in the $25-30
range; and several unknown brand caps with ceramic insulation (no
vernier). Mike's Electronics also offers a custom-made dual gang
polyvaricon with about 320 pF per section; it does not have
vernier tuning. (The URM-25D cap doesn't have built in vernier
tuning either.)
I will say right now that the latest "0219" version cap does not
test any better than the previous two Oren Elliott caps and
actually tests somewhat poorer/lower Q. This is beginning to lend
credence to Dave Aichelman's comments about these caps seem to
deteriorate in selectivity/Q when used in FSLs that are exposed to
cruddy conditions such as coastal salt air, and that cleaning the
cap can restore it to "as-new" condition.
My tests are at three frequencies, near 540 kHz for the N50-384P
max capacitance; 1000 kHz; 1700 kHz.
73,
Steve AA7U
URM-25D variable cap ("holy grail" cap)
536 kHz 816Q 996 kHz 716 Q 1698
kHz 505Q
Small Russian dual gang cap with
vernier, single gang tested
537 kHz 791Q 1000 kHz 695Q 1699
kHz 495Q
Larger Russian dual gang cap with
vernier, single gang tested
538 kHz 780Q 1000 kHz 678Q 1701
kHz 464Q
Unknown brand dual gang cap with
ceramic, no vernier, single gang tested
539 kHz 757Q 1000 kHz 660Q 1701
kHz 455Q
Mike's Electronics custom dual gang
polyvaricon (about 320 pF max per gang),1 gang
(575 kHz 561Q) 1004 kHz 536Q
1702 kHz 409Q
N50-365P Oren Elliot cap with vernier
(385pF)
538 kHz 604Q 999 kHz 503Q 1701
kHz 274Q
N50-384P version 0217 cap with vernier
538 kHz 614Q 1004 kHz 499Q 1700
kHz 276Q
N50-384P version 0219 (latest) cap with
vernier (395pF measured)
532 kHz 555Q 999 kHz 386Q 1698
kHz 195Q
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Ultralight Radio DXing Go Case - July 2020
My constant search for a radio carry case has continued...
With my focus on Ultralight radio DXing, my radio kit has changed, a couple of radios have been removed and I was finding my previous case with it's custom wooden dividers to be too heavy. After looking at the price of replacement foam, I decided this was not worth the price, being almost as much as a totally new case.
I was out doing some shopping recently when I called passed my local Bunnings store, here I found this new case for $30, I decided to replace my previous case as I found it was not working as well as I would have liked. My plan being to use my previous case for my work tools and use this new case for my Ultralight radio DXing kit.
I started off at home by sitting all my radios and other pieces of my DXing kit on the foam to see how they would all fit best. After this I cut the foam to suit and pulled out the required sections. I have now added some cloth tape to hold the foam in place.
Overall, I am very pleased with how well this case has come out, I am able to carry and store multiple radios, log sheets, pens, notes, spare batteries and ear phones, everything I need for portable sessions. It is also small enough to fit in my back pack. For $30 it provides a great level of protection. Using the foam means that each item has a home and that they are well protected, it is also much lighter than my previous cases, meaning I will carry it with me more often. It really wins on the price v size v quality scale.
While this case was designed for ultralight DXing the same ideas could be used for amateur radio, radio scanning or any other radio storage need.
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Long Term DX Project - 9/07/2020
Date: 9/07/2020
Time: 8:00
Location: St Georges Square, Launceston Tasmania
Notes: A portable morning session using my AR-1780 and 3” FSL aerial. Some excellent signals on the Victorian 50kw big guns and even 2CA on 1053kHz hit an average signal level.
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Freq
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Callsign
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Logged
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531
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3GG
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GOOD
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549
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2CR
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AVERAGE
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594
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3WV
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EXCELLENT
|
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621
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3RN
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EXCELLENT
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774
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3LO
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GOOD
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1053
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2CA
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AVERAGE
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1179
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3RPH
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WEAK
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1341
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HPON GEELONG
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AVERAGE
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1422
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HPON MELBOURNE
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AVERAGE
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1503
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3KND
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AVERAGE
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https://ultralightradiodxing.blogspot.com/
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Long Term DX Project - 8/07/2020
Date: 8/07/2020
Time: 19:00
Location: Home, Launceston Tasmania
Notes: A session at home using my AR-1780 and 3” FSL aerial.
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Freq
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Callsign
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Logged
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531
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3GG
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Excellent
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549
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2CR
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Excellent
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594
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3WV
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Excellent
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621
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3RN
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Excellent
|
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774
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3LO
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Excellent
|
|
1053
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2CA
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GOOD
|
|
1179
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3RPH
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AVERAGE
|
|
1341
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HPON GEELONG
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GOOD
|
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1422
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HPON MELBOURNE
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GOOD
|
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1503
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3KND
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AVERAGE
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https://ultralightradiodxing.blogspot.com/
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Re: Oren Elliot latest "0219" series variable cap?
Thanks again Gary,
Those 140mm rods look great! Don't know how I missed them. Ordered 40 of them this morning. They cost only about $32 Canadian more than 30 of the 125mm rods I was considering would have. If I decide to go with the 1162 strand Litz wire, with 60 feet of it, and 40 ferrite rods, I should be able to build something somewhat larger than the 3 inch, 28 rod, 'Baby' FSL. Waste not, want not. And it will, no doubt, work better.
Will likely order one of those caps from Mike's, but I have a brute of a dual section with about 440 in one section and 500 in the other and a three to one geared drive. Will see how that works to start.
Thanks for the history lesson too!
Regards,
Gord
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Re: Review - Digitech AR-1780 Multi-band Radio Receiver
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Review - Digitech AR-1780 Multi-band Radio Receiver
The AR-1780 is the big brother of the AR-1733 which has been my go-to ultralight DXing radio for a number of years. The AR-1780 covers the AM and FM broadcast bands along with the shortwave, long wave and air band. This includes RDS on the FM band and SSB on the shortwave band.
From the Jaycar website:
“This is a very compact world band radio, covering the most popular frequencies. It features rapid digital tuning, 1000 memory presets, and an easy to read display. Single Sideband Modulation (SSB) is used to listen in on 27MHz CB radio, short wave amateur radio and morse code. The large internal speaker provides clear audio, and you can connect your favourite set of headphones for personal listening. Powerful enough to receive what you want, and compact enough to take wherever you want.”
Features:
- FM/MW/SW/LW/AIR Bands
- Single Side Band (SSB)
- Telescopic Antenna
- 3.5mm socket for external antenna
- Selectable Bandwidth: 1 - 6kHz
- Radio Bands:
FM 87.5 - 108MHz
MW 522 - 1620kHz / 520 - 1710 kHz
SW 1711 - 29,999kHz
LW 150 - 450kHz
AIR 118 - 137kHz
Product Dimensions
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Height
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95mm
|
|
Weight
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0.253kg
|
|
Depth
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30mm
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|
Width
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150mm
|
Radio Receiver
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MW(AM) Frequency Range
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522kHz-1710kHz
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Power Source
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Battery
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SW Frequency Range
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1711kHz-29999kHz
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|
SW Frequency Range
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150kHz-450kHz
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Type of Radio
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FM
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FM Frequency Range
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87.5MHz-108MHz
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Power from disposable battery
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Battery used for
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Main Product
|
|
Size / Shape
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AA
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|
Battery quantity
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4pc
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|
Batteries included
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No
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|
Batteries can be replaced by user
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Yes
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Warranty: 12 Months
AM Band:
The performance on the AM broadcast bands is very good, in most cases better than my AR-1733, this has made the AR-1780 my current “go to” radio. It is very sensitive and tuning across the band is very enjoyable. The built-in ferrite antenna works well, and it matches up nicely with my 3” FSL aerial for long distance / serious DXing needs.
FM Band:
The AR-1780 features RDS which shows station names, song names and other information, this works well. Side by side testing with the AR-1733 shows a slight edge to the AR-1780 on audio quality and ability to pull in signals, a couple of community station which are iffy at best on the AR-1733, are much better and clearer on the AR-1780.
Shortwave Band:
Shortwave coverage is from 1711 kHz to 29999 kHz in 1 kHz steps. The main rotary tuning control on the side of the radio can be set to 5kHz or 1 kHz steps and there is a fine-tuning control on the right-hand side that is used for the USB and LSB modes. The radio uses the inbuilt telescopic antenna for the entire shortwave band. My experience and focus is not on this band so my experience is limited, from my limited testing it works as well as a radio of this size / price point could be expected to.
Longwave Band:
Coverage is from 150 kHz to 450 kHz. Our local beacon on 242kHz comes in well enough. Again, this band is not an area I know much about and it has very limited use here in Australia.
Air Band:
This covers from 118 MHz to 137 MHz in the AM mode. I have programmed in my local tower, ATC and AWIS frequencies and I find I often leave this locked on one of them while I am working, the gentle sounds of the ATC controllers and pilots are good background noise. While not a “scanner”, this does have a one-time search mode and will save any found frequencies for later review. Performance wise, it works as well as any of my scanners would and for listening over an extended period, the squelch mode is very helpful. I find around a 3 the best setting.
Pros:
It works well given the price and size of the unit, as a step up from the AR-1733, it fills the gap between this and the full-size radios. AM performance is an improvement on the AR-1733 and the choices of AM bandwidths really helps with hunting down stations. FM BCB is covered well. Airband is acceptable with no issues.
Cons:
Slight gap in audio while changing frequencies, delay in switching between USB and LSB modes. Weird charging voltage. Lack of carry case included.
Summary:
I am a big fan of this radio and it has taken over from my AR-1733 as my main DXing rig, for $99 on special, it is excellent value.
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Re: Oren Elliot latest "0219" series variable cap?
Gary DeBock
On Tue, Jul 7, 2020 at 12:19 PM, Gord Seifert wrote:
I just looked on Mike's site and can not find a part with any reference to Oren Elliot. I do see this..
https://www.mikeselectronicparts.com/product/384pf-air-variable-capacitor-with-81-planetary-reduction-drive/ But, the price is SO much less than on the Oren Elliot site that I can hardly believe it is the same. No problem with Mike's price, but no way am I paying well over twice as much to Oren Elliot. And, in the photo, the one on Mike's does not look anywhere near as pretty. Is the Oren Elliot version really that beautiful, or is that simply a computer generated image?
Hi Gord, The "N50 384P" variable cap from Mike's Electronic Parts (at the link you posted above) is exactly the same as the one from Oren Elliot Products, despite the much cheaper price. Oren Elliot is the OEM for the component, and has always charged higher prices (I have ordered from both sources, in the past). <<< Also, I have been looking for ferrite rods. I came up with this: https://tinyurl.com/ybk5amyr Looks to be the same material you use (same seller too) but is considerably shorter at 125mm. Also MUCH less expensive. Would this work reasonably well for someone who does not need the absolute nth degree in performance? The 10mm x 200mm version is completely out of the question due to price. >>>
The 125mm x 8mm ferrite rods are perfectly fine for FSL use, although if you would like significantly cheaper 140mm x 8mm ferrite rods than the ones that "Alexer1" sells (which are also slightly higher in gain than the 125mm variety), try this link from my friend Dennis ("sovtube," on eBay) https://www.ebay.ca/itm/Russian-Large-balun-ferrite-rods-8x140-mm-Lot-of-20-NEW-High-Quality/164167133643?hash=item26391fa9cb:g:PekAAOSwYaFWfwfH
I have dealt with both of these sellers multiple times on eBay, and can assure you that Dennis will always provide the best price and service, if he has the ferrite rods that you are looking for.
<<< One other question. Did you actually test the various different ferrite mixes for suitability while designing you FSLs? Or is it just a basic, known, fact that, for this frequency range, NiZn 400 permiability works best for this application? >>>
To be honest, the reason why I use the Russian surplus 400-permeability ferrite rods in almost all of my FSL antenna designs is because back in 2011 (when the U.K.'s Graham Maynard introduced modern FSL antennas), the cost of this Russian surplus ferrite was dirt cheap, and the early FSL experimenters like Steve Ratzlaff, Kevin Schanilec and yours truly bought up a ton of it. I still have loads of this stuff stashed away, which cost about a third of what it costs currently. Of course I have nobody to blame but myself for the explosion in ferrite price, since immediately after I publish an FSL construction article the Ukrainian eBay sellers quickly jack up the price on the ferrite type I suggest, so that some weird cases result like the 140mm x 8mm ferrite rods actually costing more than the 160mm x 8mm ferrite rods in 2016. After noticing this in 2016 I published a 3.5" FSL construction article using the 160mm x 8mm ferrite rods, and the eBay sellers promptly evened out their prices :-)
Gary
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